Receptive field

About: Receptive field is a research topic. Over the lifetime, 8537 publications have been published within this topic receiving 596428 citations.

Microstimulation of single tactile afferents from the human hand. Sensory attributes related to unit type and properties of receptive fields.

Abstract: Tungsten microelectrodes were inserted percutaneously into the median nerve of alert human subjects for recording and stimulation of single nerve fibres. Impulses from mechanoreceptive units in the glabrous skin of the hand were recorded and single afferents were characterized with respect to unit type (FA I, FA II, SA I, and SA II), as well as size and shape of receptive field, and force threshold. The electrode was then reconnected to an electrical stimulator and short pulse trains (0.25 to 0.5 s, 20 to 100 Hz) were delivered at successively increasing current intensity, while the subject was asked to report any sensation that he noticed in the hand. The first sensation was always that of a localized skin deformation within a small area, typically 2 to 3 mm in diameter, often coinciding with the receptive field of the recorded unit. Spatial matching was also found in many cases for the size, shape and orientation of the perceptive and receptive fields, strongly suggesting that the sensation was accounted for by the recorded unit that had been selectively activated by the current pulses. There were clear differences between group data associated with the four types of units with regard to the quality of the percepts. Vibratory sensation was reported with all FA II units and was common with FA I units, whereas a sustained indentation was often associated with SA I units. Indirect evidence suggested that activation of SA II units usually did not elicit a sensation. It was confirmed that a single impulse in a single FA I unit may elicit a sensory response in the attending subject, whereas a much larger input was required from SA I units, which are also less sensitive to mechanical stimuli. This was one of several findings supporting the impression that differential receptive properties, even within a group of afferents, were associated with different sensory responses. It was concluded that a train of impulses in a single tactile unit may produce within the brain of the subject a construct which specifies with great accuracy the skin area of the unit's terminals as well as a tactile subquality which is related to unit properties.

The most numerous ganglion cell type of the mouse retina is a selective feature detector

Abstract: The retina reports the visual scene to the brain through many parallel channels, each carried by a distinct population of retinal ganglion cells. Among these, the population with the smallest and densest receptive fields encodes the neural image with highest resolution. In human retina, and those of cat and macaque, these high-resolution ganglion cells act as generic pixel encoders: They serve to represent many different visual inputs and convey a neural image of the scene downstream for further processing. Here we identify and analyze high-resolution ganglion cells in the mouse retina, using a transgenic line in which these cells, called “W3”, are labeled fluorescently. Counter to the expectation, these ganglion cells do not participate in encoding generic visual scenes, but remain silent during most common visual stimuli. A detailed study of their response properties showed that W3 cells pool rectified excitation from both On and Off bipolar cells, which makes them sensitive to local motion. However, they also receive unusually strong lateral inhibition, both pre- and postsynaptically, triggered by distant motion. As a result, the W3 cell can detect small moving objects down to the receptive field size of bipolar cells, but only if the background is featureless or stationary—an unusual condition. A survey of naturalistic stimuli shows that W3 cells may serve as alarm neurons for overhead predators.

Properties of Somatosensory Synaptic Integration in Cerebellar Granule Cells In Vivo

Abstract: In decerebrated, nonanesthetized cats, we made intracellular whole-cell recordings and extracellular cell-attached recordings from granule cells in the cerebellar C3 zone. Spontaneous EPSPs had large, relatively constant peak amplitudes, whereas IPSPs were small and did not appear to contribute substantially to synaptic integration at a short time scale. In many cases, the EPSPs of individual mossy fiber synapses appeared to be separable by their peak amplitudes. A substantial proportion of our granule cells had small receptive fields on the forelimb skin. Skin stimulation evoked explosive responses in which the constituent EPSPs were analyzed. In the rising phase of the response, our analyses indicated a participation of three to four different mossy fiber synapses, corresponding to the total number of mossy fiber afferents. The cutaneous receptive fields of the driven EPSPs overlapped, indicating an absence of convergence of mossy fibers activated from different receptive fields. Also in granule cells activated by joint movements did we find indications that different afferents were driven by the same type of input. Regardless of input type, the temporal patterns of granule cell spike activity, both spontaneous and evoked, appeared to primarily follow the activity in the presynaptic mossy fibers, although much of the nonsynchronized mossy fiber input was filtered out. In contrast to the prevailing theories of granule cell function, our results suggest a function of granule cells as signal-to-noise enhancing threshold elements, rather than as sparse coding pattern discriminators or temporal pattern generators.

Converging influences from visual, auditory, and somatosensory cortices onto output neurons of the superior colliculus.

Abstract: 1. Physiological methods were used to examine the pattern of inputs from different sensory cortices onto individual superior colliculus neurons. 2. Visual, auditory, and somatosensory influences fr...